
The Rec. 601 luma coefficients were
computed using the technique that
I explained in
Luminance coeffi-
cients,
on page 250, using the NTSC
primaries and white point of
Table 22.2, on page 238.
from those of Rec. 709. For tristimulus values greater
than a few percent, use these equations"
R'240 = 1.1115 R 045 - O. 1115
G'240 = 1.1115G ~ - 0.1115 Eq 24.4
B'240 = 1.1115B ~ -0.1115
The sRGB specification for desktop computing uses
numerical values slightly different again (page 267). For
tristimulus values greater than a few percent:
1
RsRGB =
1.055 R
2.4 _
0.055
1
G'sRGB = 1.055G 2-4 -0.055